public class Demo {
    public static void main(String[] args) {
        //演示，获取整数int的最大值
        int biggest = Integer.MAX_VALUE;
        System.out.println("biggest = " + biggest);

        //演示，获取圆周率
        double pi = Math.PI;
        System.out.println("pi = " + pi);

        int  age = 18;
    }
}
